Lights in the approach area of a runway have been until recently mounted above the ground. With the advent of the large jet aircraft, runways have been extended for take off and the threshold and some approach lights previously mounted above the ground now must be recessed semi-flush into the extended runway surface. These lights house high power quartz lamps which generate a sizable quantity of heat which must be dissipated by the fixture. The light fixture itself must also be rugged enough to carry the weights of heavy jet aircraft using the runway extension. The light emitted from the threshold and approach lights must be in accordance with a predetermined pattern.